Cephalosporins having a ureido substituted acyl sidechain and various groups in the 3-position are disclosed by Erickson in U.S. Pat. No. 3,673,183, Welch et al. in U.S. Pat. No. 3,708,479, Dolfini in U.S. Pat. No. 3,833,568, Breuer in U.S. Pat. No. 3,860,591, and Breuer et al. in U.S. Pat. Nos. 3,996,217, 3,996,218, and 4,024,135, and Belgian Pat. No. 833,640.
Various 7.alpha.-methoxy cephalosporins having a ureido substituted acyl sidechain and various groups in the 3-position are disclosed by Dolfini in U.S. Pat. Nos. 3,978,051, 3,989,693, 3,989,697, 4,000,134, and 4,061,852.
Ochiai et al. in U.S. Pat. No. 4,098,888 disclose cephalosporins having an iminothiazolyl acetamido acyl sidechain with an amino, hydroxy, or imino group on the .alpha.-carbon atom of the acyl sidechain.
Cephalosporins having an iminothiazolyl or substituted iminothiazolyl acetamido acyl sidechain and various groups in the 3-position are disclosed by Numata et al. in German Offenlegungsschrift No. 2,461,478. Similarly, desmethoxy cephalosporins having an alkoxyimino or hydroxyimino substituted iminothiazolyl acetamido acyl sidechain and various groups in the 3-position are disclosed in Belgian Pat. Nos. 850,662; 852,860; 852,427; 853,545; and 856,045.